Enka is characterised by the use of melismatic progressions and long draw-out notes with vibrato in performance to emphasise the emotional lyrical contents, usually the sad aspects of life such as the pang of pain of separated young couples, the sorrow of unrequited love or lovesickness, nostalgia for the homeland during endless wanderings, the desire for affection in this transitory life and suicide or death.
Fairly enough, it doesn't really tell what enka is because it is hard to describe music in words. Nevertheless, with the aid of our music experience and some imagination, we can always draw an analogy. Just as how I tell my Western colleagues when asked what Shanghai popular song is. It sounds like when Bing Crosby met Bejing opera – just imagine a female singer singing in a high-pitched, nasal voice to the accompaniment of an American big band.
There is a classic interpretation from Barbara's Enka Site, so realistic that I can't resist citing, i.e. copying and pasting:
Team up a songwriter who writes old-fashioned Gypsy music with a romantic lyricist of an American blues or country music background. Then translate the lyrics into poetic but old-fashioned Japanese and arrange the music for a band made of half Japanese musicians and half European classical musicians, plus a harmonica and electric guitar.Is it any clearer? If not, watch this clip, a performance of 'Kawa no nagare no you ni' (川の流れのように, 'As the river flows') by the queen of enka Hibari Misora (美空 ひばり).